Abstract

The drugs of plant origin have served through the ages as the mainstay for the treatment of human ailments. The knowledge of drugs derived from medicinal plants, therefore, goes back to pre-historic times. The man, as a savage, most has known by experience how to relieve his sufferings by the use of herbs growing around him. The historical analyses of traditional medicine reveals that in his search for food the primitive men began to distinguish those plants suitable for nutritional purposes from others possessing definite pharmacological actions.
Sizeable contributions towards the knowledge of plant based drugs have been made by various civilizations including the Muslim and Greek civilizations. In the Indo Pak sub-continent there has been a fairly organized effort for pharmaco-chemical studies in the physiological active plant constituents. The H.E.J Research Institute of Chemistry, which is among the finest institute of the world in natural product chemistry, founded in 1967 by the world renowned scientist late Prof. Salimmuzzaman Siddiqui. Curreently it is led by the famous scientist of Pakistan Prof. Atta-ur-Rahman. Hundreds of medicinal plants are studied annually in the Institute for the discovery of plant based medicinal compounds. The present Ph.D dissertation compiles the phytochemical investigation on two medicinal plants of Pakistan namely Duranta repens Linn. and Ehretia obtusifolia Hochst. The thesis, therefore, is presented in following two parts:
PART A "Phytochemical studies on Duranta repens Linn."
PART B ÃÂÃÂ¢ÃÂÃÂÃÂÃÂPhytochemical studies on Ehretia obtusifolia HochstÃÂÃÂ¢ÃÂÃÂÃÂÃÂ
ÃÂÃÂ¢ÃÂÃÂÃÂÃÂPhytochemical Studies on Duranta Repens Linn.
This part describes the isolation and structural elucidation of seven new compounds. In addition, three known compou8nds are reported for the first time from this species.
New compounds isolated from Duranta repens
Compounds isolated for the first time from Duranta repens
1Cleomiscosin A (151) 2(+) Hardwickiic acid (152) 3(+)-3,13-Clerodadien-16,15-olid-18-oic acid (153)
Compounds already reported from Duranta repens
1(-)-6ÃÂÃÂÃÂÃÂ²-Hydroxy-15, 16-expoxy-5ÃÂÃÂÃÂÃÂ²,8ÃÂÃÂÃÂÃÂ²,9ÃÂÃÂÃÂÃÂ²,10ÃÂÃÂÃÂÃÂ±-cleroda-3,13(16), 14-trien-18-oic acid (154) 26,7,8,-Trimethoxycoumarin (155) 35,4,ÃÂÃÂ¢ÃÂÃÂÃÂÃÂ-Dihydroxy-3,6,7-trimethoxyflavone (156) 43,7,4ÃÂÃÂ¢ÃÂÃÂÃÂÃÂ-Trihydroxy-3ÃÂÃÂ¢ÃÂÃÂÃÂÃÂ-(4-hydroxy-3-methylbutyl)-5,6-dimethoxyflavone (157) 53,7-Dihydroxy-3ÃÂÃÂ¢ÃÂÃÂÃÂÃÂ-(4-hydroxy-3-methylbutyl)-5,6,4ÃÂÃÂ¢ÃÂÃÂÃÂÃÂ trimethoxyflavone (158) 6Betulin (159) 7Stigmaterol (160) 8Stigmasterol 3-O-ÃÂÃÂÃÂÃÂ²-D-glucopyranoside (161) 9ÃÂÃÂÃÂÃÂ²-Sitosterol 3-O-ÃÂÃÂÃÂÃÂ²-D-glucopyranoside (162)
An Overview of Part B
ÃÂÃÂ¢ÃÂÃÂÃÂÃÂPhytochemical Stdies on Ehretia Obtusifolia HochstÃÂÃÂ¢ÃÂÃÂÃÂÃÂ. This part describes the isolation and structural elucidation of three new compounds along with seven known compounds reported for the first time from this species. New compounds isolated from Ehretia obtusifolia Compounds isolated for the first time from Ehretia obtusifolia 1Methyl rosmarinate (181) 2Rosmarinic acid (182) 3Quercetin 3-O-ÃÂÃÂÃÂÃÂ²-D-glucopyranoside (183) 4Quercetin 3-ÃÂÃÂÃÂÃÂ²-D-glucopyranosy1-4-O-ÃÂÃÂÃÂÃÂ²-D-glucopyranoside (184) 5Ursolic acid (185) 6ÃÂÃÂÃÂÃÂ²-Sitosterol (186) 7ÃÂÃÂÃÂÃÂ²-Sitosterol 3-O-ÃÂÃÂÃÂÃÂ²-D-glucopyranoside (187)
Apart from the chemical work, pharmacological studies on the isolated compounds have also been undertaken to ascertain their therapeutic potentials.